The European Scrutiny Committee released a report Tuesday that said whatever Cameron negotiates cannot possibly be agreed and be legally "binding and irreversible" — which Cameron has demanded — anytime ahead of the referendum.
They conclude that voters taking part in the referendum will have been made promises by Cameron, which he cannot possibly be sure of, as any renegotiation of the EU treaties will require the consent of each member states — and possibly even referendums in some countries.
The report comes just two days before Cameron meets other EU leaders to consider his wish list, as set out in a letter to the European Council President Donald Tusk. Cameron was already facing opposition from virtually every other member on his plans to make EU migrants working in the UK wait four years before enjoying in-work benefits.
— David Cameron (@David_Cameron) December 14, 2015
The Chairman of the Committee, Sir Bill Cash, said: "Our report is clear that the only way in which the Prime Minister's negotiations could be given the legally binding and irreversible effect which he himself has called for — even for minor reforms to the EU, let alone a fundamental change in the UK's relationship with the EU — would be through Treaty amendment, or the equivalent agreement of a Protocol. These would be lengthy processes, and each Member State would have to agree using its own constitutional procedures including, in some countries, referendums.
"Whatever the promises made in the negotiations, there is no certainty that they will be delivered to the British people. Voters in the forthcoming referendum must be aware of this when they make their choice as to whether to vote to remain in the EU or to leave the EU," Sir Bill Cash said.
Cameron's renegotiation wish list includes an opt-out from "ever closer union" and a recognition that the EU has other currencies than the euro and that non-euro countries shall not be discriminated against by any further integration of the Eurozone.
He also wants individual states to be able to club together and defeat some measures imposed by the EU and is calling for bureaucracy to be cut. Both ideas have support among other leaders.
He is likely to perform a U-turn on the in-work benefits, at his meeting with EU leaders on December 17, but will seek to find enough 'wiggle room' on other measures. Cameron will have the backing of most of his counterparts sympathetic to his position — the need to assuage strong Euroskepticism in the UK, but a desire to remain inside an EU, provided reforms are made.
However, the committee report Tuesday, is likely to throw into doubt whether anything he negotiates can really be put to the electorate in an In/Out referendum by the end of 2017, as he had promised, as it could take years for his renegotiations to be ratified.